Mining of sulfur using heated water and an impervious barrier



March 12, 1957 w, T FREY 2,784,954

MINING OF SULFUR USING HEATED WATER AND AN IMPERVIOUS BARRIER Filed Sept. 7, 1954 2 Sheets-Sheet l Hummm?,

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| l ml'ulll' lllllimllHHHnllufmllllrlll MINING F SULFUR USING HEATED WATER AND AN HMPERVIUS BARRIER William T. llfrey, New rleans, La., assigner, by mesne assignments, to Esso Research and Engineering Company, Elizabeth, N. J., a corporation of Delaware Application September 7, 1954, Serial No. 454,385 7 Claims. (Cl. 262-3) covery of sulfur is obtained from a subsurface earth deposit.

The present invention may be briefly described as a method for mining sulfur by liquefaction by heated mine water which comprises injecting into a well bore penetrating a subsurface sulfur deposit a fluid sealing material having a specific gravity lower than the specific gravity of the mine water. The sealing material is placed in the subsurface deposit and forms an impervious barrier or a barrier having a permeability substantially less than that of the unmined formation in the subsurface deposit in the normal path of upward movement of the mine water.

Thus in the present invention the heated mine water is injected into the subsurface sulfur deposit through a well bore penetrating the deposit at a temperature above the melting point of sulfur to liquefy the sulfur deposit. The liquefied sulfur is then produced until the consumption of mine water which flows out into the sulfur-containing formation begins to increase abnormally. Thereafter, the injection of heated mine water is terminated and replaced by a Huid sealing material having a specic gravity lower than the specic gravity of the mine water. The fluid sealing material is forced out into the sulfur deposit in the path of the normal path of mine water and forms an impervious barrier or a barrier having a permeability substantially less than that of the unmined formation which causes the heated mine water when injection of same is resumed to ow under the barrier and to liquefy additional sulfur and thereby recover sulfur which heretofore `might not be recovered without consumption of large amounts of water.

In conducting the present invention, the sulfur deposit is penetrated by a well casing which is cemented in place and the casing is then penetrated through the entire interval of the sulfur producing deposit. A pipe tubing is then run into the perforated casing which has a telescoping tubular member arranged therein to which is attached a packing member.

Arranged within the tubing and the `telescoping member is a smaller tubing for injection of air to carry the melted sulfur to the surface.

Thus as the barrier member is formed, the packing member is lowered on the telescoping arrangement and perforations below the barrier member are uncovered to allow the heated mine water to be injected into the deposit just below the barrier member. This series of operations is repeated as the sulfur becomes progressively liquefied down the deposit.

The present invention will be further illustrated by reference to the drawing in which 2,784,954 Patented Mar. i2, 1957 lCC Figs. 1 to 6 are a stepwise illustration of the practice of the invention.

Referring now to the drawing, numeral 11 designates a well bore which penetrates a sulfur deposit 12. The well bore has arranged therein a casing 13 which is cemented in place withprimary cement 14. in the several figures of the drawing the casing 13 and cement 14 have been penetrated, such as with a gun perforator, to form perforations 15 extending the entire length or depth of the sulfur deposit 12.

Arranged within the casing 13 is a tubing string 16 which is telescopically arranged on the tubing member 17 and makes a sliding connection therewith with packing means 18.

The lower end of the tubing 16 is provided with a packing member or swab cups 19 which serve to direct heated mine water 1@ through the annulus 2t) into the sulfur deposit 12 along the path indicated by the arrows. The heated mine water 10 at a temperature of about 300 F. and preferably under a pressure above 100 p. s. i. liquees or melts the sulfur from sulfur deposit 12 and the liquefied sulfur 12a is thus caused `to ow into the bottom of the well 11 through the perforations 15 below the packer 19 and thence upwardly through the tubing member 17 and tubing string 16 by way of the annulus 21, the liquid sulfur being lifted to the earths surface, not shown, by means of air introduced through a small pipe 22.

After the amount of heated mine water increases to an extent which has become economically unattractive, and forms a path or pattern such as indicated by the dashed lines, the injection of heated mine water is terminated and a batch of sealing material having a specic gravity less than the specific gravity of the heated mine water is introduced down the annulus 2@ and directed into the formation 12 in the normal path 23 of the heated mine water. This sealing material proceeding out through the perforations 15 above the packing member 19 forms a barrier 24 which causes the heated mine water to flow underneath barrier 2li when the flow thereof is resumed as indicated in Fig. 2, the telescoping tubing 16 and tubing member 17 having been lowered to lower the packing member 19 to uncover perforations 15 below the barrier 24. Thereafter additional sulfur is liqueed from the sulfur deposit 12 and caused to flow to the bottom of the well and then up the annulus 21 and lifted to the earths surface by means of air injected through pipe 22.

Referring now to Figs. 3 and 4, the barrier 24 having been formed in the deposit 12 and additional sulfur having been removed therefrom to provide a second normal path of flow of the mine water, such as illustrated by 25, and the mine water consumption has again become uneconomical, the telescoping tubular members 16 and 17 having been moved to lower the packing member 19 as shown in Fig. 3. The flow of mine water is terminated and a second batch of the sealing material is injected down the annulus 2h and directed through the perforations 15 above the packer 19 to form a second barrier 26. Thereafter, additional perforations 15 are uncovered below the barrier 26 to cause the mine water 1t), the injection of which is down the annulus'Ztl, to flow under the barrier 26 and to liquefy additional quantities` of sulfur from the deposit 12, the liquefied sulfur 12a entering the perforations 15 below the packer 19 and flowing into the well up the annulus 21 and lifted to the earths surface by air introduced by pipe 22.

In Figs. 5 and 6, the barrier member 19 has been lowered further on the tubing 16 and tubing member 17 to provide a third path of llow 27 for the mine water to liquefy additional sulfur from the deposit 12. The barriers 24 and 26 directing the mine water underneath the barrier 26,. to cause substantially complete removal ofthe sulfur from the deposit 12 as shown in Fig. 6.

It is within the contemplation of the present invention to inject the sealing material intermittently or periodical- 1y tov torno barriers` for the flowof heated mine water as the sulfur is liqueed from the deposit. By means of interposing an impervious barrier or a barrier having a permeability substantially less than the permeability of the unmined formation in the path of the mine water, it ispossible to remove and recover substantially completely all of the sulfur in the sulfur deposit.

The sealing material employed in the practice of the present invention may be a material which will set up under the conditions encountered in the sulfur deposit and may suitably be an aerated slurry of cement and oil which on encountering water in the sulfur deposit will set up and form an impervious barrier or a barrier having a permeability substantially less than the permeability of the unmined formation. The slurry of cement and oil may suitably be Portland cement adrnixed with a hydrocarbon, such as kerosene. Other hydrocarbons besides kerosene may be used, such as diesel oil, crude oil, fractions thereof and the like. The oil may be used in an amount in the range from about 76.6 to 6.10 weight percent of 36 grav. diesel oil to provide a cement slurry having a specic gravity in the range from 1.0 to 1.1 with no aeration. With aeration these percentages of oil may be reduced to a lower ligure to about 40 to 60 Weight percent.

It is contemplated that other types of cements may be used in the practice of the present invention provided the specific gravity is lower than the specific gravity of the mine water which is usually'a saturated brine. It is considered within the purview of my invention to add weighting materials to the saturated brine to increase the weight thereof and to allow the use of sealing materials normally heavier than Saturated brine. As an example of materials which I may add to the saturated brine mention may be made of calcium chloride, and the like.

The present invention is of considerable utility in that it is possible to obtain good penetration of mine water substantially throughout the sulfur deposit and, therefore, recover substantial amounts of sulfur which heretofore were left in the deposit. Furthermore, this invention reduces the necessity of pumping excessive volumes of mine water and also eliminates the necessity of injecting mud in an attempt to reduce the volume of mine water.

The nature and objects of the present invention having been completely described and illustrated, what I wish to claim as new and useful and to secure by Letters Patent is:

1. A method for mining sulfur in a well bore having a casing arranged therein which comprises perforating said casing, to form perforations extending through the sulfur deposit, isolating selected perforations in said casing in the upper level of said deposit, injecting heated mine water into said deposit through said isolated perforations to liquefy sulfur from said deposit, producing said liqueed sulfur, terminating injection of said heated mine water, injecting through said isolated perforations into said deposit a hardenable slurry of cement in oil having a specie gravity less than the specific gravity of said mine water, `lisplacing mine water with said sealing material adjacent the upper portion ofV said deposit and hardening said sealing material to thereby form an impervious barrier in said deposit in the normal path of upward movement of said mine water, isolating additional perforations in said casing below said barrier, injecting heated mine water through said additional isolated perforations to liquefy additional amounts of sulfur from said deposit, producing said liquefied sulfur and then repeating said series of operations as sulfur becomes depleted from said deposit.

2. A method as in claim 1 wherein said slurry is a nonaerated slurry of Portland cement containing from about 24.4 to about 39 weight percent of Portland cement in from about 76.6 to about 61.0 weight percentof oil, said sllirry 1htving a specilic gravity in the range from about 3. A method as in claim l wherein said slurry isV an aerated slurry of from about 60 to 40 weight percent of Portland cement with `from 40 to 60 weight percent of oil. Y

4. ln a method for mining, sulfur in a subsurface sulfur deposit wherein heated mine water is introduced into said sulfur deposit at a temperature above the melting point of said sulfur to liquefy the same and wherein said liqueied sulfur is produced from said well, said mine watertending to ilow upwardly to the upper portion of said sulfur deposit during said mining operations, the improvement which comprises the steps of periodically discontinuing the ow of mine water into said deposit and dur-.i

ing each said period of discontinued mine Water flow. injecting through said well into the upper pontion of said sulfur deposit a hardenable slurry of cement in oil, vsaid slurry having a specific gravity less than the specific gravity of said mine water and hardening said slurry adjacent the upper portion of said sulfur deposit whereby, on reintroduction of said mine water, sulfur in a lower pontion of said deposit may be more readily recovered.

5. A method for mining sulfur through a Well penetrating a subsurface sulfur deposit which comprises the steps of injecting heated mine water into said deposit through said well at a temperature above the melting point of said sulfur to liquefy said sulfur at least :adjacent the upper portion of said deposit, producing said liquefied sulfur, whereby an accumulation of said mine water adjacent said upper portion of said deposit will tend to occur, terminating the injection of said heated mine water, injecting through said well a slurry of cement in oil having a specilic gravity less than the speoic gravity of said mine water to displace said accumulation of mine water adjacent the upper portion of said deposit, hardening said slurry to form an impervious barrier in said subsurface deposit adjacent the upper portion thereof and then'resuming the injection of said heated mine water into said subsurface deposit below said barrier to liquefy additional quantities of sulfur in said deposit.

6. A method as in claim 5 wherein said slurry is a nonaerated slurry of Portland cement containing from about 24.4 to about 39 weight percent of Portland cement in from about 76.6 to about 61.0 weight percent of oil, said slurry having a specific gravity in the range from about 1.0 to 1.1.

7. A method as in claim 5 wherein said slurry is an aerated slurry of from about 60 to 40 weight percentk of Portland cement with from about 40 to 60 weight percent of oil.

References Cited in the le of this patent UNITED STATES PATENTS 

5. A METHOD FOR MINING SULFUR THROUGH A WELL PENETRATING A SUBSURFACE SULFUR DEPOSIT WHICH COMPRISES THE STEPS OF INJECTING HEATED MINE WATER INTO SAID DEPOSIT THROUGH SAID WELL AT A TEMPERATURE ABOVE THE MELTING POINT OF SAID SULFUR TO LIQUEFY SAID SULFUR AT LEAST ADJACENT THE UPPER PORTION OF SAID DEPOSIT, PRODUCING SAID LIQUEFIED SULFUR, WHEREBY AN ACCUMULATION OF SAID MINE WAWTER ADJACENT SAID UPPER PORTION OF SAID DEPOSIT WILL TEND TO OCCUR, TERMINATING THE INJECTION OF SAID HEATED MINE WATER, INJECTING THROUGH SAID WELL A SLURRY OF CEMENT IN OIL HAVING A SPECIFIC GRAVITY LESS THAN THE SPECIFIC GRAVITY OF SAID MINE WATER TO DISPLACE SAID ACCUMULATION OF WATER ADJACENT THE UPPER PORTION OF SAID DEPOSIT, HAV ING SAID SLURRY TO FORM AN IMPERVIOUS BARRIER IN SAID SURFACE DEPOSIT ADJACENT THE UPPER PORTION THEREOF THEN RESUMING THE INJECTION OF SAID HEATED MINE WATER 